938 REPORT—-1890: 
long before'a range of 3,000 yards was attained the chance of hitting an object 
became extremely small. 
It is desirable to give some idea of the accuracy, or rather want of accuracy, of 
these guns. 
In 1858 I was appointed secretary to the first Committee on Rifled Cannon, 
and the early experiments showing how extraordinary was the accuracy of the 
new weapons, it became a matter of importance to devise some means of comparing 
in this respect the old and the new guns. 
The plan I proposed was one which has since been followed by the artillerists of 
nearly all countries. It was to calculate the probable error in range and the 
probable error in deflection, and from these data the area within which it would 
be an even chance that any given shot would strike; or, in other words, that area. 
within which, out of a large number of rounds, half that number would fall. This. 
area was for the smooth-bored gun at a range of 1,000 yards, 147-2 yards long by 
9°1 yards broad, or 1,339:5 square yards, while the similar area for the rifled gun 
at the same range was 23:1 yards long by 08 yard broad, or an area of 18°5 
square yards. But the great decrease of accuracy due to an increase of range with 
the smooth-bore guns is especially remarkable. Experiments showed that with 
the smooth-bored gun an increase of range of only 350 yards more than doubled 
the error in deflection, and made the area selected for comparison 206 yards long 
by 20:2 broad, or 4,161 square yards, as nearly as possible trebling the area for ap 
increase in range of 35 per cent. 
But I have not done yet. These experiments were made with the same lots of 
powder carefully mixed, and the irregularities in velocity would be such as are due 
to manufacturers’ errors only. But the variations in the energy developed by the 
gunpowder employed have still to be considered. In 1860, being then an associate 
member of the Ordnance Committee, I carried on for the Government the first. 
electro-ballistic experiments made in this country. My attention was early called 
to the great variation in energy developed by powders recently made and pro- 
fessedly of the same make, and I pointed out that in my experiments the variations 
between one lot of powder and another amounted occasionally to 25 per cent. 
of the total energy developed. It is unnecessary to say that on service, and when 
powder had been subjected to climatic influences, the variations would have been 
much greater. 
The variations in energy of new powder were chiefly due to the method of proof 
then in use, the Eprouvette mortar, than which nothing can be conceived better 
adapted for passing into the service powders unsuitable for the guns of that 
time. 
But with the want of accuracy of the gun itself, and the want of uniformity in 
the propelling agent, it may easily be conceived that a limit was soon reached 
beyond which it was mere waste of ammunition to fire at an object even of con- 
siderable size, and we can appreciate the reasons which led our nayal commanders, 
whenever possible, to close with their enemy. 
When we come to consider guns of the present day, the first point that attracts — 
our attention is the enormous increase in the size and weight of the larger natures. : 
It may fairly be asked indeed if, weight for weight, the modern guns are so much © 
more powerful than the old, and, if we have command of such great ranges, why ~ 
such heavy guns should be necessary. 
The answer to this, of course, is that it has been considered essential to have 
guns capable of piercing at short distances the thickest armour which any ship 
can carry, and this demand has led us from guns of 5 tons weight up to guns of 
110 and 120 tons weight, and to the development of the important mechanical 
arrangements for working them, to which I shall presently refer. 
On the principles which guide the construction of these large guns I shall say 
little, both because the subject is too technical to be dealt with in an address, and 
because the practice of all nations, though differing in many points of detail, in 
essentials is closely accordant. 
On three points of construction we lay particular stress in this country. These 
points are: That the gun shall be strong enough to resist the normal working 
